Atomic Structure + Radioactivity Flashcards
What is the structure of an atom?
An atom consists of:
• Nucleus (containing protons and neutrons)
• Electrons orbiting the nucleus in electron shells.
What are protons, neutrons, and electrons?
• Protons: Positively charged particles in the nucleus.
• Neutrons: Neutral particles in the nucleus.
• Electrons: Negatively charged particles orbiting the nucleus.
What is the atomic number?
The number of protons in the nucleus of an atom. It defines the element.
What is the mass number?
The total number of protons and neutrons in an atom.
What is an isotope?
Atoms of the same element with the same number of protons but different numbers of neutrons (and therefore different mass numbers).
What is radioactivity?
The spontaneous decay of the nuclei of certain elements, resulting in the release of radiation (alpha, beta, or gamma).
What are the three types of radiation?
Alpha (α): Consists of 2 protons and 2 neutrons. It has a +2 charge and is the least penetrating.
2. Beta (β): A fast-moving electron with a -1 charge. It can penetrate more than alpha particles but is stopped by materials like plastic or glass.
3. Gamma (γ): Electromagnetic radiation (like X-rays). It has no charge and is the most penetrating type of radiation.
What is the symbol for each type of radiation?
Alpha (α): \text{He}^2_4 (helium nucleus)
• Beta (β): \text{e}^-_0 (electron)
• Gamma (γ): \gamma (photon)
How can you protect yourself from alpha radiation?
Alpha radiation can be stopped by a sheet of paper or the outer layer of skin.
How can you protect yourself from beta radiation?
Beta radiation can be stopped by a sheet of plastic, glass, or a few millimeters of aluminum.
How can you protect yourself from gamma radiation?
Gamma radiation requires thick lead or several meters of concrete to be shielded effectively.
What is nuclear decay?
The process by which an unstable nucleus loses energy by emitting radiation.
What is half-life?
The time it takes for half of the atoms in a sample of a radioactive substance to decay.
How do you calculate the remaining amount of a substance after a certain number of half-lives?
• After one half-life, half of the substance remains.
• After two half-lives, one-quarter remains.
• After three half-lives, one-eighth remains, and so on.
How do you find the half-life of a substance from a graph?
The half-life is the time taken for the amount of radioactive substance to decrease by half on the graph.
What are some uses of alpha radiation?
• in smoke detectors (detecting smoke by ionizing air).
• Medical tracers (to treat cancers, for example).
What are some uses of alpha radiation?
• in smoke detectors (detecting smoke by ionizing air).
• Medical tracers (to treat cancers, for example).
What are some uses of beta radiation?
• Thickness monitoring (used in factories to check the thickness of materials like paper or aluminum).
• Medical tracers in imaging.
What are some uses of gamma radiation?
• Sterilizing medical equipment (as gamma rays can kill bacteria and viruses).
• Cancer treatment (Gamma rays can be used to kill cancer cells).
What is nuclear fission?
The process in which a heavy nucleus splits into two smaller nuclei, releasing energy. This is used in nuclear reactors.
What is nuclear fusion?
The process where two light nuclei combine to form a heavier nucleus, releasing energy. This process powers the sun.
What are the main differences between fission and fusion?
• Fission: Splitting of a heavy nucleus.
• Fusion: Combining of light nuclei.
• Fission is used in nuclear power stations, while fusion is the process that powers stars.
What are the risks of ionizing radiation?
Ionizing radiation can damage cells and DNA, potentially causing cancer or mutations. Prolonged exposure can lead to radiation sickness.
How can exposure to radiation be minimized?
- Distance: Increase distance from radiation source.
- Time: Minimize exposure time.
- Shielding: Use appropriate materials to shield from radiation.
